Upper trunk
Encyclopedia
The upper trunk is a trunk of the brachial plexus
which derives from the C5 and C6 roots.
Damage to the upper trunk causes:
Arm hangs by side,
Elbow can’t flex,
Arm medially rotated,
Forearm pronated,
‘waiter’s tip’,
Loss of sensation over deltoid (C5) and lateral upper limb (C6).
The suprascapular nerve (C5,C6) arises from the upper trunk of the brachial plexus beneath the fascial floor of the posterior triangle, before it passes beneath the transverse scapular ligament and round the lateral border of the scapular spine.
The musculocutaneous and median nerve
s derive largely from this trunk.
Brachial plexus
The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...
which derives from the C5 and C6 roots.
Damage to the upper trunk causes:
Arm hangs by side,
Elbow can’t flex,
Arm medially rotated,
Forearm pronated,
‘waiter’s tip’,
Loss of sensation over deltoid (C5) and lateral upper limb (C6).
The suprascapular nerve (C5,C6) arises from the upper trunk of the brachial plexus beneath the fascial floor of the posterior triangle, before it passes beneath the transverse scapular ligament and round the lateral border of the scapular spine.
The musculocutaneous and median nerve
Median nerve
The median nerve is a nerve in humans and other animals. It is in the upper limb. It is one of the five main nerves originating from the brachial plexus....
s derive largely from this trunk.